Air exhauster for a rotary pneumatic machine

ABSTRACT

An air exhauster for a rotary pneumatic machine is disclosed having an annular boss and a central projection having a tapped hole therein positioned on the body casing of a rotary pneumatic machine. An exhaust groove is formed between the boss and the central projection and a connecting hole is located at the bottom of said loop exhaust groove so that it can connect with an exhaust hole of an air motor fixed in the body casing. A partition board is located within the exhaust groove adjacent to said connecting hole, and an insulation board with an air hole is mounted on the upper edge of the loop boss. The outer side of said insulation board is covered by a bowl-shaped exhaust cover which has exhaust ports at one part of its periphery, and may be fastended by a single bolt which screws into the tap hole of said projecting navel.

United States Patent 1191 [none 1 1 AIR EXHAUSTER FOR A ROTARY PNEUMATIC MACHINE [75] Inventor: Katashi lnoue, Nara City, Japan Fuji Kuuki Kabushiki Kaisha, Osaka, Japan i 22 Filed: Jan. 12, 1973 21 Appl. No.: 323,081

[73] Assignee:

[30] Foreign Application Priority Data [58] Field of Search.... 181/36 R, 36 A, 33 K, 35 R, 181/35 B, 49, 57; 417/312 [56] References Oited UNITED STATES PATENTS 1,747,876 2/1930 Metzgar 181/49 2.222.703- 11/1940 Bixler 417/312 UX 2.642.843 6/1953 Krohm "181/36 A ux June 4, 1974 Murphy 181/36 A UX Rosen et a1. 181/36 A 57] ABSTRACT An air exhauster for a rotary pneumatic machine is disclosed having an annular boss and a central projection having a tapped hole therein positioned on the body casing of a rotary pneumatic machine. An exhaust groove is formed between the boss and the central projection and a connecting hole is located at the bottom of said loop exhaust groove so that it can connect with an exhaust hole of an air motor fixed in the body casing. A partition board is located within the exhaust groove adjacent to said connecting hole, and an insulation board with an air hole is mounted on the upper edge of the loop boss. The outer side of said insulation board is covered by a bowl-shaped exhaust cover which has exhaust ports at one part of its periphery, and may be fastended by a single bolt which screws into the tap hole of said projecting navel.

3 Claims, 11 Drawing Figures III . 1 AIR EXHAUSTER FOR A ROTARY PNEUMATIC .MACHINE The present invention relates to an air exhauster for a rotary pneumatic machine like an air grinder or an air wrench, which makes it possible to absorb the noise of exhaust coming out of an air motor and to lead the exhaust to an optional direction.

It is well known that as an air motor of this kind is required to be small and light and to have a high output, it inevitably produces a large exhaust noise spoiling the environment for work and causing a public nuisance.

In order to absorb such exhaust noise, the proir art employs methods such as providing a large exhaust chamberinside the body of a pneumatic machine and lowering an exhaust pressure in the chamber and then leading the exhaust out of the machine or such as providing a small exhaust chamber at an exhaust hole and filing the chamberwith a noise absorbing material such as sponge.

However, the first method has a dis-advantage in that providing a largeexhaust chamber makes the whole of the machine larger'and heavier and accordingly makes the operation of the machine inconvenient.

The second method, though the size of the machine does not become large, has such disadvantages that the moisture contained in the exhaust condenses in the noise absorbing material filled in a small exhaust chamher and chokes up the meshes of the filling material.

This problem is particularly acute in the winter season since the condensed moisture freezes and completely chokes up the meshes of the filling material due to which, the exhaustresist'ance becomes large, exhaust pressure of the motor goes up and the output of the motor drops. I

Moreover, the exhaust port of conventional pneumatic machines is of an immovable design for releasing the exhaust in a fixed direction, due to which it is impossible to change the direction of the exhaust port. Such a limitationon the direction of the exhaust port has made the operation of machine very inconvenient.

The object of the present invention is to offer an air exhauster which absorbu the exhaust noise without making the body of a pneumatic machine large and without dropping the output of the motor, and which can be connected very simply by means of a single bolt, and which makes it possible to face its exhaust port in any desired direction. I

Other objects relating to the details of economy and construction will appear more fully hereinafter, as shown in the accompanying drawings and as finally pointed out in the appended claims.

In the accompanying drawings:

FIG. 1 is a vertical sectional front view of the main part of an air grinder equiped with air exhauster of the present invention;

FIG. 2 is a horizontal sectional plane view along I] line in FIG. 1;

FIG. 3 is a vertical sectional side view along Il-II line in FIG. 2;

-III line in FIG. 2;

FIG. 5 is a horizontal sectional plane view along IIII- -IIII line in FIG. 2;

FIG. 6 is a vertical sectional front view of the air grinder with a bowl-shaped exhaust cover having a different structure than the device of FIGS. 1 and 2;

FIG. 7 is a vertical side view along VV line in FIG.

FIG. 8 is a horizontal sectional plane view along VI--VI line in FIG. 6;

FIG. 9 is a vertical sectional front view of the air grinder with a bowl-shaped exhaust cover which is of a structure being different from that shown in FIG. 2 and 6;

FIG. 10 is a vertical sectional side view along VII- VII line in FIG. 9;

FIG. 11 is a horizontal sectional plane view along VIII-VIII line in FIG. 9.

On one side of a body casing 1 of an air grinder which contains an air motor 2 and an output shaft 5 which is connected to said air motor 2 through a pair of bevelan exhaust chamber 10 for the air motor in the body casing 1. A partition board 12 is provided adjacent said connecting hole 11. The upper edges of the loop boss 6, the central projection 7 and the partition board 12 are all made to be on the same level, onto which an insulation board 13 with an air hole13' isapplied. A bowl-shaped exhaust cover 14 having a plurality of small exhaust ports 14 in a certain region on its peripheral surface is put on the outer side of thus applied insulation board 13 and is fastened by a single bolt 15 which screws into the tapped hole 8 of said projection 7. (see FIG. 1 FIG. 5) a FIG. 6 FIG. 8 illustrate a bowl-shaped exhaust cover 14 provided with small exhaust ports 14' at one part of its circumference, and also has a zigzag passage formed on its inner peripheral surface by means of plural interrupting boards 17 which project radially from a pipe 16 mounted on a bolt 15 on different levels from one another. The exhaust cover is placed on the outer side of the abovementioned insulation board 13 and then is fastened by said bolt 15 which screws into the tapped hole 8 of said projecting navel 7.

FIG. 9 FIG. 11 illustrate plural bowl-shaped exhaust covers 14, 18, 19 wherein the lowest cover 14 having a hole 14 on its top is mounted upon the outer side of said insulation board 13 and the middle cover 18 having a hole 18 on its top is mounted upon said lowest cover 14 and the top cover 19 with a plurality of small exhaust ports at one part of its circumference is mounted upon the middle cover 18. Then, these exhaust covers are fastened by a single bolt 17 which screws into the tapped hole 18 of said projection 7.

Under such structure-as above stated in FIG. 1 FIG. 5, the exhaust discharged from the exhaust hole 2' of the air motor 2 to the exhaust chamber 10 is led therefrom to the exhaust groove 9 surrounding the boss 6 through the connecting hole 11. The exhaust, after having almost completed circled the projection in the exhaust groove 9, is discharged to the bowl-shaped exhaust cover 14 through the air hole 13 of the insulation board 13 which is applied onto the upper edge of the exhaust groove 9. Then, it is discharged into the air through the exhaust ports 14 provided at one part of the exhaust cover 14.

In the case of the device of FIG. 6 FIG. 8, the exhaust discharged from the exhaust hole 2' of the air motor 2 to the exhaust chamber is led therefrom to the exhaust groove 9 surrounding the boss 6 through the connecting hole 11. The exhaust, is led from the exhaust groove 9, into the fan-shaped chambers partitioned by the interrupting boards 17 inside the bowlshaped exhaust cover 14 through the air hole 13 of the insulation board 13 which is applied onto the upper edge of the exhaust groove 9. Then, it is discharged into the air through the exhaust ports 14 provided at one part of the exhaust cover 14. ln the device embodied in FIG. 9 FIG. 1 l, the exhaust discharged from the exhaust hole 2' of the air motor 2 to the exhaust chamber 10 is led therefrom to the exhaust groove 9 surrounding the boss 6 through the connecting hole 11. The exhaust, after having almost circled the boss in the exhaust groove 9, is led into the lowest exhaust cover 14 through the opening 13 of the insulation board 13 applied onto the upper edge of the exhaust groove 9, wherefrom it passes to the middle cover 18 through the hole 14 provided on the top of the lowest cover 14,

passes to the top cover 19 through the hole 18 provided on the top of the middle cover 18, and finally it is discharged into the air through the exhaust ports 19' provided at one part of the top cover 19.

Thus, such processes as the squeezing of the exhaust, the releasing andexpansion of the exhaust is a large chamber and the change of direction of the exhaust are repeated alternately several times and the exhaust pressure from the air motor falls gradually. As the result, the noise of exhaust from the exhaust ports 14' is reduced considerable and there is almost no fear of causing a problem of public nuisance by noise. During the abovementioned processes, the resistance to the flow of exhaust is so small that the exhaust pressure of the air motor 2 does not go up and accordingly the output of the motor does not drop. Further, the bowl-shaped exhaust covers l4 l8, 19 are so designed as to be laid one upon another and to be fastened by a single bolt in the center, which not only makes it very simple to assemble and dismantle the cover but also makes it possible to face the exhaust ports 14 in any desired direction by turning the top cover 14 with the bolt 15 as the center. Thus, a pneumatic machine equiped with the air exhauster of the present invention can be used very conveniently without being limited by the direction of the air exhauster.

Moreover, the bowl-shaped exhaust cover 14, l8, 19 can be manufactured by punch pressing of a thin metal plate or diecasting of a light alloy or moulding of synthetic resin, so that it does not add much to the weight of a machine. And yet, since it is possible to freely choose the size of these exhaust and the location and number of holes when changing the number of exhaust covers to be piled up, it has high effect on the absorption of noise. It is also possible to fill any or all of the exhaust covers freely with a noise absoring material. ln this case, these exhaust covers are so large that the choking up of meshes of the filling material does not occur as frequently as in prior art devices. Even if the choking up does occur, it is possible to clean or replace the noise absorbing material simply by means of a single bolt. Further, the air exhauster of the present invention is excellent in appearance, simple in structure and cheap in price.

As seen in the foregoing paragraphs, the air exhauster of the present invention has many great advantages. It is needless to say that the present invention can be applied not only to the air grinder shown in the attached drawings but also to any other rotary pneumatic machine. Further, it was observed that even where on partition board 12, is used almost the same noise absorbing effect could be obtained.

What I claim is:

1. An air exhauster for a rotary pneumatic machine, comprising:

a machine casing having an annular boss on one side of said casing and a central projection having a tapped hole in the center of said projection, said projection being located centrally of said boss, said boss and said projection defining an exhaust groove thereinbetween, said exhaust groove haing a communicating hole operatively located therein communicating with an air motor exhaust hole; a partition board located in a vertical plane within said groove adjacent said communicating hole; an insulation board having an air hole therein mounted on said boss and covering said groove; and a bowl shaped exhaust cover having a plurality of exhaust ports located in one region-of said cover positional over said insulation board and having a central aperture through which a fastening screw may be inserted into said tapped hole for fastening said cover over said insualtion board.

2. The air exhauster as recited in claim 1 wherein said bowl shaped cover further comprises a plurality of interrupting boards horizontally placed within said cover in a stacked relation and having openings situated so as to form a zig zag exhaust passage within said bowl shaped cover.

3. The air exhauster as recited in claim 1 further comprising a plurality of bowl shaped exhaust covers in stacked relation, said plurality of covers each having a central aperture and being connected to said machine casing by a single fastening member. 

1. An air exhauster for a rotary pneumatic machine, comprising: a machine casing having an annular boss on one side of said casing and a central projection having a tapped hole in the center of said projection, said projection being located centrally of said boss, said boss and said projection defining an exhaust groove thereinbetween, said exhaust groove haing a communicating hole operatively located therein communicating with an air motor exhaust hole; a partition board located in a vertical plane within said groove adjacent said communicating hole; an insulation board having an air hole therein mounted on said boss and covering said groove; and a bowl shaped exhaust cover having a plurality of exhaust ports located in one region of said cover positional over said insulation board and having a central aperture through which a fastening screw may be inserted into said tapped hole for fastening said cover over said insualtion board.
 2. The air exhauster as recited in claim 1 wherein said bowl shaped cover further comprises a plurality of interrupting boards horizontally placed within said cover in a stacked relation and having openings situated so as to form a zig zag exhaust passage within said bowl shaped cover.
 3. The air exhauster as recited in claim 1 further comprising a plurality of bowl shaped exhaust covers in stacked relation, said plurality of covers each having a central aperture and being connected to said machine casing by a single fastening member. 